To integrally sinter an oxide electrolyte and a cathode or anode, preventing a cathode or anode active material from reacting at an interface, is needed. Therefore, there is a demand for lowering the sintering temperature of an oxide electrolyte.
To sinter an oxide electrolyte at low temperature, there are attempts to lower the sintering temperature by addition of an additive, promote grain growth by addition of a sintering agent, form a raw material into fine particles by a coprecipitation method or the like, etc.
For example, Patent Literature 1 discloses a method for producing a garnet-type ion conducting oxide, the method comprising the steps of: mixing a base material comprising a main component represented by the basic composition Li7+X−Y(La3−X, AX(Zr2−Y, TY)O12 (where A is at least one of Sr and Ca; T is at least one of Nb and Ta; and X and Y satisfy the following conditions: 0≤X≤1.0 and 0≤Y<0.75) and additive components including lithium borate and aluminum oxide; molding the mixture; and sintering the molded product at 900° C. or less.
Patent Literature 2 discloses a garnet-type ionic conductive oxide subjected to partial substitution of Li with H.
Patent Literature 1: Japanese Patent Application Laid-Open (JP-A) No. 2015-041573
Patent Literature 2: JP-A No. 2012-096940